The telecommunications environment is one of continuous evolution and technological advancement. Whereas historically it consisted strictly of analog POTS (Plain Old Telephone Service), supported by the PSTN, this environment has expanded to include not only the Mobile network but also, more recently, digital data transmission of increasing quantity and speed, supported by the Internet.
Prior to the introduction of the Internet, a class of telephony services usually known as Single Number Service (SNS) or Personal Number Service (PNS) had been introduced in the marketplace to address the mobility and call management needs of telephony network subscribers. The main characteristic of this class of services was, and still is, to provide call routing based on customer-programmed schedules, usually implemented through proprietary service logic, residing on either Service Control Points (SCP), an Advanced Intelligent Network (AIN) or Intelligent Network (IN), or on special purpose switch adjuncts or service nodes. The Internet has had an important effect on these telephony services, increasing not only the number of events and conditions influencing call completion decisions, but also the number of mechanisms available to reach a called party, as well as the number of potential call delivery points. Correspondingly, a co-pending patent application entitled "System and method for communication session disposition responsive to events in a telecommunications network and the Internet", filed on Dec. 18, 1997, Ser. No. 05/994,008 and assigned to Northern Telecom Limited, now allowed discloses a communication session disposition mechanism able to make decisions regarding communication session disposition based on a broader range of events. The subject invention includes primarily a novel Service Logic Controller (SLC) responsive to events occurring in a telecommunications network (PSTN or Mobile network) or a data communications network (such as the Internet) for making decisions regarding the disposition of different communication sessions, for instance a telephone call or a fax transmission.
However, until such a flexible communication session disposition mechanism becomes ubiquitous in the telephony system, placing a call on the Internet telephony network will require a lot more from the caller than placing a call on the PSTN. The caller must first be connected to the Internet in order to figure out the address of the person to be called, and must also know where to look for this address. Another option available today is to use the services of Internet Telephony Service Providers (ITSP). In such a case, the caller must call into a voice-over-IP (VOIP) gateway, where IP stands for Internet Protocol, and supply the called party directory number. The gateway then routes the call through the Internet to the gateway closest to the called party and completes the call over the PSTN. If the called party happens to be connected to the Internet at the moment of calling, the caller will most likely end up listening to a busy signal, or may be connected to the called party's voice mailbox. If the call is completed anyhow, the caller might end up paying unnecessary toll charges for the last leg of the call if the called party does not live in an area deserved by the VOIP gateway. In all cases, the caller must explicitly know some extra information (IP address, VOIP gateway director number), and must perform some extra steps in order to place the call.
Some companies offer a service based on proprietary devices to simplify the establishing of a call between two parties over the Internet. An example of such a service is the Internet appliance commercialized by Aplio in the United-States. More information may be found on this topic at the Internet address (www.aplio.com). Unfortunately, the disadvantages of such a service are that both ends must own a special device, both ends must have a subscription to an Internet Service Provider (ISP), and the communication session setup requires an extended period of time.
In summary, when a caller wishes to establish a call within the Internet domain, the caller must find the IP address of the called party through the means of different services available within the Internet domain. In other words, work and effort is required on the part of the caller; it is not automatic. Even if the caller wanted to complete a call from the Internet domain into the PSTN domain, a PSTN/IP gateway is required. The caller must therefore determine the address of such a server in the vicinity of the called party in order to avoid toll charges.
Thus, there exists a need in the industry to simplify and refine the process of using the Internet domain, in tandem with both the PSTN and Mobile network, for calling purposes within modern telephony systems.